The present invention relates generally to mobile communications networks and, in particular, to a network architecture utilizing functional distribution of location registers to provide uniform subscriber handling independent of access technology.
Conventionally, a mobile communications system usually comprises a central operations facility, having a home location register (HLR), and a plurality of local coverage areas. All data associated with a particular subscriber unit (e.g. mobile phone number, rate plan)is stored as a subscriber profile record in the HLR. Each local coverage area typically comprises a mobile switching center (MSC) and a visitor location register (VLR. As a subscriber unit roams into a given MSC service area, a temporary copy of that subscriber""s profile record is downloaded to the VLR in the local switching center handling call traffic for the area. The local copy typically expires once a subscriber unit leaves the given MSC service area. The HLR tracks the location of each subscriber unit in the system; and each time a new MSC is utilized, the HLR receives a location update.
As such, conventional mobile networks and topologies present a number of problems and challenges to system designers and users. Since the subscriber records in the VLR are local copies of the subscriber records in the HLR, conventional mobile architectures need mechanisms to keep all multiple copies of the data consistent (e.g. an update of the VLR in case data is modified in the HLR). Furthermore, the HLR very often becomes a bottleneck in case of a restart/reload of either the MSC/VLR or the HLR. This is due to the numerous location updatings, where the HLR provides copies of the subscriber profiles to the VLRs, occurring upon restart/reload.
Recently, some communications systems have decoupled control signaling and user payload. Conventional systems generally have backbone networks independent of access networks. The backbone networks, which typically include service profiles and mobility management servers, should be rather transparent to the access technology used at the moment. The service profiles should still consider the specifics of the access technology (e.g. low bandwidth characteristics in case of a mobile access), but the profile should generally remain the same, and only parameters in the profile should be adapted. Currently, conventional mobility management parts (typically located in the HLR) are not able to cope with different access technologies.
Other problems and challenges are also presented by conventional mobile networks and topologies. Conventional VLR and HLR structures handle both subscriber services and mobility, thus these nodes are characteristically rather complex, and hardly scalable. Integration with global mobility mechanisms (e.g. Mobile IP) is further complicated due to the combined nature of the HLR and VLR structures. Replication or distribution the HLR/VLR structures is very difficult if not functionally impossible, since these are mixed nodes (mobility management and subscriber profiles) of tightly coupled functional areas. Further, complicated procedures are required to provide inter-working between the HLR and VLR and other subscriber profiles, such as a subscriber profile in an H.323 or SIP (Session Initiation Protocol) type of network.
Previously, local copies of the HLR profiles (i.e. the VLRs) were distributed all over the networks in case of roaming. Data was kept consistent via mechanisms like location updating, mobile subscriber purging, etc. Because the achievable transmission speeds in conventional networks were relatively slow, this distributed caching of the subscriber profiles was seen as the only feasible option. One major shortcoming of such approaches was that each network had its own profile and mobility management databases. Inter-working between subscriber profiles in different networks was either not considered, not possible, or not feasible given system performance and constraints. For example, conventional systems ordinarily would not be able to determine which service profile should have priority where several profiles apply for a specific traffic case. Such situations, if encountered at all, were commonly addressed on a case by case basis.
Therefore, versatile architecture for mobile networking that fully utilizes performance and throughput of advancing communications technology in a simple and cost-effective manner while eliminating the need for special mechanisms to keep data consistent across the network in case of restarts and profile modifications is now needed, providing robust and efficient profile inter-working and prioritization while overcoming the aforementioned limitations of conventional methods.
The present invention provides for network architectures with roaming functionality, but without requiring local copies of subscriber records. The present invention provides profile and mobility registers or servers, reconfiguring and optimizing operations previously accomplished by HLR/VLR structures. The present invention decouples user access technology and methods from the type of subscription service that user has; simplifying operation and providing scalability in new profile and mobility handling.